Dyed acrylonitrile containing textile having controlled shrinkage and processes for forming same



United States Patent Ofifice 3,069,218 Patented Dec. 18, 1962 3,069,218DYED ACRYLONITRILE CONTAINING TEXTILE HAVING CONTROLLED PROCESSES FORFORMING SAME Julius Hermes, Martinsville, Va. N Drawing. Filed June 30,1959, Ser. No. 823,851 1 11 Claims. (Cl. 817) This invention relates toacrylonitrile containing polymeric yarn or filaments having deep dyepenetration and high shrinkage characteristics. More particularly, itrelates to arapidly efiective dyeing of the yarn or filaments with ahigh, controlled shrinkage by first dyeing and shrinking theacrylonitrile container polymeric yarn or filaments in a heated aqueousbath containing alkylene carbonate and then drawing to improve theirphysical properties whereby subsequent heat treatment after knitting orweaving shrinks the dyed yarn or filaments to substantially theiroriginal length.

In the manufacturing of high bulk yarn, pile fabrics, made by weaving orknitting, and the like where the filaments must undergo a controlledshrinkage to produce various effects such as bulking of the yarn orthickening of the pile, it is necessary that the filaments or a part ofthe filaments used be capable of a high controlled shrinkage after thefilaments have been drawn to improve their physical properties. Also, itis necessary to have stable coloration of the filaments before usage.Acrylonitrile containing polymeric yarn or filaments used in themanufacture of bulk yarns or pile fabrics exhibit only limited shrinkageafter being drawn. This lack of high filament shrinkage decreases thequality of the bulk yarn, pile fabric and like material made from thedrawn filaments. 7

Commercial drawing of the filaments is accomplished by heating thefilaments to a temperature of 220 F. to 320 F. and then mechanicallystretching the filaments while in heated condition. Substantiallyoriented acrylonitrile containing filaments, such as Orlon 42 (DuPont),can be elfectively drawn up to about 30 percent and when heated in arelaxed state will shrink to their original length, If the filaments aredrawn beyond 30 percent, subsequent relaxation and heating will produceonly a Shrinkage of about 30 percent. Thus, by using conventionalmethods of drawing and shrinking a 30 percent shrinkage is all that canbe achieved regardless of the amount of drawing of the filaments. Whereun'oriented acrylonitrile containing polymeric filaments such as OrlonL-7 (DuPont) are drawn, the filaments become brittle and at high pointof stretch (less than 30 percent) break thus making it diflicult toobtain a high shrinkage.

These and other disadvantages are. overcome by first immersingacrylonitrile containing polymeric filaments in a heated aqueous bathcontaining alkylene carbonates and a dye stuflf where initial shrinkageand drying takes place and then drawing the filaments either in the bathor immediatelythereaften: Filaments treated by the process of thisinvention produce dyedfilarnents having a high, controlled shrinkagewhich will shrink when heated in a relaxed condition to substantiallythe degree drawn. Thus, by con-trolling the degree of drawing, apredeter mined controlled shrinkage can be produced.

By the use of the process of this invention, substantially orientedacrylic filaments, such as Orlon type 42, can be drawn beyond 50 percentanddyed and: then, shrunk to their original length when heat treated ina relaxed condition. Orlon L-7, which is difiicult to draw under normalconditions because of its brittle structure can be successfullydrawnbeyond 60 percent and dyed, with subsequent shrinkage to originallength when heated in a relaxed condition.

SHRINKAGE AND I when the solution is neutral or close thereto.

Also, unoriented acrylic filaments, such as Typical of the polymericmaterial which may be treated by the process of this invention are .thewell-known acrylonitrile type polymeric filaments both oriented andunoriented which include those containing at least 50 percent by weightacrylonitrile units in the polymer chain; for example,po-lyacrylonitrile and its copolymers and interpolymers of acrylonitrilewith other polymerizable monomers. These monomers include, among others,vinyl acetate, vinyl chloride, acrylic and methacrylic acids orderivatives and homologues thereof, styrene, methyl vinyl ketone, vinylpyridines, such as 2-vinyl, 4- vinyl, 5-ethyl-2-vinyl or2-methyl-5-vinyl pyridine and isobu-tylene or other similarpolymerizable hydrocarbons.

Exemplary of alkylene carbonates used in the bath of this invention arethe alkylene carbonates having 3 to 5 carbon atoms. Among the moreimportant of these carbonates are ethylene carbonate, propylenecarbonate, trimethylene carbonate, tetramethylene carbonate, 2,3-butylene carbonate, glycerine carbonate, and the like, ethylene andpropylene carbonate being preferred.

Typical dyestuffs which can be used to effect the dyeing ofacrylonitrile filaments include some of the acid dyes, basic dyes,disperse dyes and the like. It has been found that these dyes exhaustrapidly from the dye bath However, good dye exhaustion from the bath isprovided when the pH ranges from 2 to about 8. Any acid may be used toprovide the acid dye bath. For this purpose either an organic or aninorganic acid may be used.

The aqueous alkylene carbonate bath contains a small percentage of thedyestufi dispersed therethrough to effect dyeing of the filaments whilepreparing the structure for drawing. It has been found that the shade ofcolor can be controlled by the concentration of the alkylene carbonatein the bath. For example, alkylene carbonate in the range of 2 to 20percent by volume produces excellent dye exhaustion from the bath withinshort contact time. Where lighter shades are desired the lower portionof the range can be used, the percentage of the alkylene carbonate useddepending on the shade of dyeing desired. It has also been found thatafter the upper portion of the range has been reached, the addition ofmore alkylene carbonate does not substantially affect dye exhaustion.

In carrying out the process of this invention the acrylonitrilecontaining filaments are passed through a heated aqueous bath containingthe alkylene carbonate and a dyestuff. The filaments are quickly heatedto the temperature of the bath which effects rapid penetration of thealkylene carbonate from the liquid and allowing penetration of thedyestuft throughout the filament structure. The penetration is deep anduniform, which is evidenced by the fact that a small amount of residualtreating liquid remains imbedded in the filament even after thoroughWashing and drying. It is believed that the small residual amount ofalkylene carbonate in the filaments aids in the realignment of themolecule of the filaments as they are being drawn so thatthere is thegreatest possible degree of elasticity within the filament structure toallow for the increased drawing strength. The substantially uninhibitedrealignment of the molecules produced by the shrinkage in the bath isincreased. Excellent results have been obtained for filament tow whenthe alkylene carbonate concentration is from 6 to percent by volume.

Advantageously, the temperature of the bath may be maintained between 80C. and its boiling point. Very good results are obtainable when the bathtemperature is at the boiling point. The bath can be maintained at a pHof from 2 to 8. Excellent results have been obtained when the bath isabout neutral. If a low pH is desired, organic or inorganic acids can beincluded in the bath to provide the desired pH.

The filaments can be drawn after shrinkage in the aqueous alkylenecarbonate bath containing dyestuff or they can be drawn after removalfrom the bath. Also, the filaments can be passed through a washing bathto remove from the surface presence of alkylene carbonate before thedrawing is accomplished. The washing bath may include a hydrolyzationagent for hydrolyzing the alkylene carbonate on the surface of thefilaments. The filaments can be exposed in the aqueous alkylenecarbonate bath from 2 to 20 seconds which allows for a rapid andeconomical continuous process for inducing into the filament structure ahigh degree of controlled shrinkage.

Where the filaments are drawn after passing through the aqueous alkylenccarbonate bath they may be maintained at a drawing temperaturesufiicient to impart plasticity to the filament so that the filamentswill not break during the drawing operation. It has been found thatacrylic filaments of the Orlon type maintained at a temperature between140 F. to 170 F. have the desired plasticity for such a drawingoperation. This plasticity, coupled with the elasticity provided by theresidual alkylene carbonate in the filament structure is believed toprovide the high degree of uniform drawing without breakage or fractureof the filament, such as is evidenced in the drawing of Orlon L-7 asheretofore described.

The process can be carried out wtih the filament tow in a relaxed statebeing first passed through the aqueous alkylene carbonate bath where thefilaments are initially shrunk and dyed. The shrunken filaments are thenpassed through a wash to remove excess bath liquid from the surface ofthe filaments. The filaments are then drawn while in a heated bathmaintained at a temperatule of from 140 F. to 150 F. by passing thefilaments over two sets of spaced rolls with the second set of rollsoperating at an increased speed. The differential in speed between thetwo sets of rolls can be set so that the desired percentage ofelongation is introduced into the filaments. Advantageously, the drawingcan take place in the treating bath immediately after the initialshrinkage of the filaments and the filaments washed and dried whileunder tension, the produced filament having therein a predeterminedshrinkage ratio.

The invention will be more clearly understood by reference to thefollowing examples which are given for purposes of illustration and arenot to be construed in any sense as limitative of the invention.

Example I A sample of raw Orlon tow (type 42) 10 inches in length wasimmersed in a bath containing 440 cc. of water, 60 cc. of propylenecarbonate and 2 grams of Latyl Violet R (DuPont) under relaxed tension.The tow was removed from the bath after 10 seconds and heated to atemperature of 160 F. and drawn to 15.4 inches and dried under tension.The tow in a relaxed state was then shrunk to 10 inches in boilingwater. Upon examination the tow exhibited a deep reddish violet colorwith excellent fastness properties. The sample showed a shrinkage of34.5 percent.

Example 11 Orlon tow was treated as set forth in Example I by immersingit in an aqueous bath containing 435 cc. of

water, 65 cc. of propylene carbonate and the same dyestuffs with thefollowing results:

Original length inches 9.8

After dyeing and drawing do 14.8

After treatment in boiling water do 9.0

Shrinkage percent 39 Example lII Orlon tow was treated as set forth inExample I by immersing it in an aqueous bath containing 430 cc. ofwater, 70 cc. of propylene carbonate and the same dyestuffs with thefollowing results:

Original length inches 10.0

After dyeing and drawing -do 16.0

After treatment in boiling water do 9.0

Shrinkage "percent" 43 Example IV Orlon two was treated as set forth inExample I by immersing it in an aqueous bath containing 425 cc. ofwater, cc. of propylene carbonate and the same dyestuffs with thefollowing results:

Original length inches 9.25 After dyeing and drawing u-.. do 14.5 Aftertreatment in boiling water do 7.5 Shrinkage percent 48 All of the towprocessed as set forth in Examples 11 through IV were tested and foundto have a deep reddish violet color with excellent fastness as well asimproved physical properties.

Example V The treating bath, as described in Example I, was used exceptthat ethylene carbonate and Sevron Red G (DuPont) was used. The dyed towexhibited the same percentage shrinkage and a deep red coloration whichwas found to have excellent fastness.

Example VI Example VII Orlon tow (type L-7) was processed as describedin Example I except that 475 cc. of water, 25 cc. of ropylene carbonateand Latyl Violet R (DuPont) was used with the following results:

Original length inches 10 After dyeing and drawing do 20 After treatmentin boiling water do 10 Shrinkage percent-.. 50

The tow exhibited a deep reddish violet color.

Example VIII Orlon tow (type L-7) was processed as described in ExampleI except that 465 cc. of water, 35 cc. of propylene carbonate and 1 gramof Quinoline Yellow M (DuPont) was used with the following results:

Original length inches 10 After dyeing and drawing do 24 After treatmentin boiling water do 10 Shrinkage percent 58 The tow showed a brightyellow coloration and excellent color fastness.

Example IX A sample of Orlon tow (type L-7) was processed as describedin Example I except that 490 cc. of water and cc. of propylene carbonatewas used with the same dyestutf with the following results:

Original length inches 10 After dyeing and drawing do 17 After treatmentin boiling water do 10 Shrinkage percent 38 As set forth in Examples VIIthrough IX, tow (L-7) was processed with ethylene and glycerinecarbonate being used in place of propylene carbonate with the same finalresults.

Several tests were conducted in which acetic acid and phosphoric acidwas used to maintain the pH of the bath below 7. The results of thesetests show that good dyed tow was obtained at low pH and a highshrinkage was produced as set forth in the foregoing examples.

It will be appreciated that the process set forth above produces dyedfilaments capable of a controlled amount of shrinkage. It has been foundthat the shrinkage is dependent on the concentration of the alkylenecarbonate in the bath as well as the percentage of draw induced into thefilament. Thusby varying the percentage of draw and the concentration ofthe alkylene carbonate filaments having predetermined percentageshrinkage characteristics can be obtained.

It will be further appreciated that the filaments processed inaccordance with this, invention possess new and different physicalcharacteristics as is apparent from the high degree of controlledshrinkage exhibited when the filaments are heated under relaxed tension.It is believed that the realignment of the molecules due to the highdegree of drawing and the residual alkylene carbonate in the filamentstructure produces the new and improved physical characteristics withbetter color distribution throughout the filament structure.

What is claimed is:

1. A process for simultaneously dyeing and inducing controlled shrinkagein polymeric filaments containing at least 50 percent by weight ofacrylonitrile, after formation and during heat processing of the yarnafter stretching, which comprises immersing said filaments in a heatedaqueous bath maintained at a temperature above 80 C. for a period offrom 5 to 20 seconds, said bath containing from 2 to about 20 percent byvolume of an alkylene carbonate having from 3 to 5 carbon atoms and adyestufl, and stretching said filaments from about 30 to 70 percent oftheir original length.

2. The process of claim 1 in which the temperature of said bath is atits boiling point.

3. The process of claim 1 in which the filaments are stretched in awater bath heated to a temperature of between 140 F. and 170 F afterremoval from said alkylene carbonate bath.

4. The process of claim 1 in which said stretched filaments in the formof textile are heated to shrink the filaments to substantially theiroriginal length.

5. A process for simultaneously dyeing and inducing controlled shrinkagein polymeric filaments containing at least 50 percent by Weight ofacrylonitrile, after formation and during heat processing of the yarnafter stretching, which comprises immersing the filaments in a heatedaqueous bath at a temperature above 80 C. for a period of from 5 to '20seconds, said bath having from 2 to about 20 percent by volume ofpropylene carbonate and a dyestuif and maintained at a pH of from 2 toabout 8, and stretching said filaments from about 30 to percent 0 theiroriginal length.

-6. A process for simultaneously dyeing and inducing controlledshrinkage in polymeric filaments containing at least 50 percent byweight of acrylonitrile, after formation and during heat processing ofthe yarn after stretching, which comprises immersing the filaments in aheated aqueous bath at a temperature above C. for a period of from 5 to20 seconds, said bath having from 2 to about 20 percent by volume ofglycerine carbonate and a dyestuff and maintained at a pH of from 2 toabout 8, and stretching said filaments from about 30 to 70 percent oftheir original length.

7. A dyed polymeric filament containing at least 50 percent by weight ofacrylonitrile, said filament having a controlled shrinkage when heattreated and having its molecular structure aligned by drawing thefilament after contact with an aqueous bath of an alkylene carbonatehaving from 3 to 5 carbon atoms and a dyestuff, and maintained at atemperature above 80 C., said filament being from about 30 to 70 percentof its original length after initial shrinkage and containing a smallamount of said alkylene carbonate within the polymer structure.

8. The polymeric filament of claim 7 in which the filament is drawn inpropylene carbonate bath.

9. The polymeric filament of claim 7 in which the filament is drawn inethylene carbonate bath.

10. The polymeric filament of claim 7 in which the filament is drawn inglycerine carbonate bath.

11. The polymeric filament of claim 7 in which the filament containing asmall amount of residual alkylene carbonate within the polymericstructure is shrunk to substantially its original length.

References Cited in the file of this patent UNITED STATES PATENTS2,173,997 Burgeni Sept. 26, 1939 2,438,968 Field et al Apr. 6, 19482,569,470 Hagemeyer Oct. 2, 1951 2,716,586 Terpay Aug. 30, 19552,869,975 Hare Jan. 20, 1959 2,931,272 Haas Apr. 5, 1960 FOREIGN PATENTS734,974 Great Britain Aug. 10, 1955

1. A PROCESS FOR SIMULTANEOUSLY DYEING AND INDUCING CONTROLLED SHRINKAGEIN POLYMERIC FILAMENTS CONTAINING AT LEAST 50 PERCENT BY WEIGHT OFACEYLONITRILE, AFTER FORMATION AND DURING HEAT PROCESSING OF THE YARNAFTER STRETCHING WHICH COMPRISES IMMERSING SAID FILAMENTS IN A HEATEDAQUEOUS BATH MAINTAINED AT A TEMPERATURE ABOVE 80*C. FOR A PERIOD OFFROM 5 TO 20 SECONDS, SAOD BATH CONTAINING FROM 2 TO ABOUT 20 PERCENT BYVOLUME OF AN ALKYLENE CARBONATE HAVING FROM 3 TO 5 CARBON ATOMS AND ADYESTUFF, AND STRETCHING SAID FILAMENTS FROM ABOUT 30 TO 70 PERCENT OFTHEIR ORIGINAL LENGTH.